Invasive PlantsInvasive Plants

Monica VernonMonica Vernon

Ecol 474Ecol 474

What is an Invasive Plant?

An invasive plant species is defined as one that has or is likely to spread and develop self-sustaining populations, and become dominant or disruptive.

Invasive plants interfere with ecosystem function and are a serious threat to biodiversity and productivity in different habitats.

Also Known As

o Invasive plants are also known by names such as weeds, and include adjectives such as alien, noxious, exotic, transient, or foreign, to name just a few

Why Does it Matter? Invasive plants are second only to habitat loss and

degradation in endangering native plant species. They are also the second most serious threat to biodiversity in all ecosystems.

Negative effects of the invasive plants can be seen in many factors including competition for resources, hybridization, introduced or increased nitrogen fixation, and increased sedimentation among other things.

Invasive weeds in wetland areas cause problems for water resource managers, can inhibit drainage and interfere with intended uses for a body of water, and also provide a habitat for vectors of diseases. A recent estimate on the cost of invasive plants was put at $35 billion a year.

History Plants original uses were medicinal and agricultural,

but over time with society acquiring more disposable wealth, they also became a hobby with ornamental gardening and experimentation. Experimental gardens, commercial nurseries, and international trade of plants and seeds flourished

Today’s interest in horticulture and plant exploration is one of the pathways of invasive plant introduction and spread. The United States has encountered various problems for over a century due to invasive plants, largely because of ornamental use or intentional introduction

How are They Being Spread? The Internet

Rarely differentiates between the plants that are invasive and those which are not.

Every aquatic plant that was listed on the federal or state noxious weed list was found on the internet. Because many are pretty and easy to grow there are problems with them being sold.

Easy access to the internet has increased the spread of invasive species. Species may now repeatedly, on larger scales than ever, be introduced to new areas

How are they Being Spread?

Botanical Gardens and Arboreta’s Usually more knowledgeable and have greater lengths of

time in observation of plant behavior, issues still arise such as invasive species being mistaken for non-invasive and problems with a period known as lag time.

One may believe a new plant safe and noninvasive due to the fact it was observed for a period of time without displaying characteristics of an invasive plant, but many invasive plants do not begin to invade for many years. Lag time for many species has still not been determined. A few reasons for this is the fact some of the invasive plants only become invasive after changes in environment, genetic changes within the plant, or introduction of pollinator.

How are They Being Spread?

Many Hobbyists/Nurseries usually don’t have the knowledge to recognize invasive species. Even those who have some knowledge of invasive species very often misidentify an invasive species for one they think to be safe.

What Can Be Done?

The results of a recent study brought two main issues to the forefront. The first issue is that people need to know what exactly is invasive. Many stated if they knew about the invasiveness of a plant they would not be involved with a purchase. The second big issue that arose from the study was that the best way to inform and educate most people as to what plants are invasive would be to place a label on the plants in the nurseries

What Has Been Done?What Has Been Done? Environmental and economic damage continue to Environmental and economic damage continue to

rise because of invasive plants. Though the United rise because of invasive plants. Though the United States government has made laws against States government has made laws against importation of species listed in the Federal Noxious importation of species listed in the Federal Noxious Weed Act (White 2001), there are still very few Weed Act (White 2001), there are still very few restrictions on importation of plants. We do not have restrictions on importation of plants. We do not have screening for invasive plants before introduction, screening for invasive plants before introduction, though Australia and New Zealand have already though Australia and New Zealand have already implemented such regulations (Hoddle 2001). Though implemented such regulations (Hoddle 2001). Though President Clinton signed an executive order for an President Clinton signed an executive order for an Invasive Species Council to be developed, little has Invasive Species Council to be developed, little has still been done to reduce the harm invasive plants still been done to reduce the harm invasive plants have caused previously or will cause in the future. have caused previously or will cause in the future. Controlling the distribution of invasive plants has also Controlling the distribution of invasive plants has also been hindered because of the threat of conflict with been hindered because of the threat of conflict with international trade agreements (White 2001). international trade agreements (White 2001).

What To Do:What To Do: If all groups involved work together to pool If all groups involved work together to pool

resources and stand up as a unified front, there resources and stand up as a unified front, there will be a better chance for action. A national plan will be a better chance for action. A national plan is needed that includes development of is needed that includes development of regulations, education programs, plant lists, and regulations, education programs, plant lists, and plant labeling (White 2001). A national plan, if plant labeling (White 2001). A national plan, if implemented, will take much gathering of implemented, will take much gathering of information, analysis, and cooperation between information, analysis, and cooperation between all involved. There must be effort to also locate all involved. There must be effort to also locate and prosecute those who intentionally grow, sell, and prosecute those who intentionally grow, sell, or distribute invasive plants (Kay 2001). or distribute invasive plants (Kay 2001).

The best thing we can do as a country to prevent The best thing we can do as a country to prevent further damage is to start educating our citizens further damage is to start educating our citizens of the dangers of aquatic plants and their effects of the dangers of aquatic plants and their effects on ecosystems around the world. on ecosystems around the world.

ReferencesReferences Hoddle, Mark S. “Restoring Balance: Using Exotic Species to Control Hoddle, Mark S. “Restoring Balance: Using Exotic Species to Control

Invasive Exotic Species”. Invasive Exotic Species”. Conservation BiologyConservation Biology 18.1. (2004). 17 18.1. (2004). 17 Septmber 2006Septmber 2006

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Kay, Stratford H., Steve Hoyle. “Mail Order, the Internet, and Invasive Kay, Stratford H., Steve Hoyle. “Mail Order, the Internet, and Invasive Aquatic Weeds.” Aquatic Weeds.” J. Aquat. Plant ManageJ. Aquat. Plant Manage. 39:88-91 (2001). 14 September . 39:88-91 (2001). 14 September 2006 2006

< < http://www.apms.org/japm/vol39/v39p88.pdfhttp://www.apms.org/japm/vol39/v39p88.pdf>> MacIssac, Hugh J., Robert J. Colautti. “ A Neutral Terminology to Define MacIssac, Hugh J., Robert J. Colautti. “ A Neutral Terminology to Define

‘Invasive’ Species”. ‘Invasive’ Species”. Diversity and DistributionsDiversity and Distributions 10, 135-141.(2004) 17 10, 135-141.(2004) 17 September 2006 September 2006 http://www.blackwell-synergy.com/links/doi/10.1111/j.1366-9516.2004.0006http://www.blackwell-synergy.com/links/doi/10.1111/j.1366-9516.2004.00061.x/pdf1.x/pdf

White, Peter, Sarah Hayden Reichard. “Horticulture as a Pathway of White, Peter, Sarah Hayden Reichard. “Horticulture as a Pathway of Invasive Plant Introductions in the United States”.Invasive Plant Introductions in the United States”. BioScience BioScience 51.2(2001). 51.2(2001). 17 Septmber 2006 http://www.bioone.org/perlserv/?request=get-17 Septmber 2006 http://www.bioone.org/perlserv/?request=get-document&issn=0006-3568&volume=51&issue+2&page=103>document&issn=0006-3568&volume=51&issue+2&page=103>